Enhancing nasal retention: using the mucosal blanket to structure sprays

Abstract The anatomy of the nasal cavity, although volumetrically relatively small, houses an effective surface area ca. 9.6 m 2 , which facilitates conditioning of air (humidity/temperature) through heat and moisture exchange using a dense vascularised network. Although effective at regulating air intake, the large surface area, permeable membranes and efficient transport systems consequently leave it vulnerable to airborne pathogens and high rates of infection. Recently, there has been a movement to improve nasal sprays, trying to maximise spray coverage whilst maintaining a viscous nature to extend residence across the mucosal lining. In this study, NoriZite®, a commercial nasal spray based on a natural polysaccharide, gellan, has been studied for its retention within healthy volunteers. Data collected shows elimination kinetics with a half-life of 4 hrs, remaining detectable in the nasal cavity for up to 6 hrs. As such, NoriZite® shows potential as a long lasting nasal barrier, which could be used for the prevention of airborne infections.